The invention also relates to an EGR system of the type referred to heretofore with the exhaust gas recirculation pipe_II, wherein no EGT is provided. In this case, a pure naturally aspirated or suction engine is involved. The connection of an exhaust gas recirculation pipe_II therefore corresponds, in the absence of an EGT, to the architecture of a low-pressure exhaust gas recirculation pipe, which branches off downstream of the compressor.
Gasoline engines include all non-diesel engines, concomitantly all external ignition engines, SI (spark ignited) engines with spark plugs, as well as, at least in certain sectors, also some self-igniting engines, and CAI (Controlled Auto Ignition) engines, which are operated with gasoline fuels such as petrol, alcohol, or gas. Diesel engines, by contrast, are self-ignition engines, HCCI (Homogeneous Charge Compression Ignition) engines, which are operated with diesel or oils or other fuels.
From U.S. Pat. No. 5,671,600 A an exhaust gas recirculation system for diesel engines is known. Provided at the exhaust gas outlet or at the exhaust pipe is a particle filter, to which an exhaust gas recirculation pipe is connected. The exhaust gas recirculation pipe opens upstream of a charge-air compressor into the inlet pipe. Provided inside the exhaust gas recirculation pipe is a valve for changing the exhaust gas mass flow. The particle filter serves to protect the charge-air compressor or the charge-air cooler against dirt contamination.
DE 10 2011 015 629 A1 describes the placement of a three-way catalytic converter inside an exhaust gas recirculation pipe of a gasoline engine in order to improve the pollutant emission, and concomitantly a reduction of HC, NOx and CO.
From EP 2 194 351 B1 a charge-air cooler with integrated diesel particle filter to protect the charge-air compressor is known.
DE 10 2012 107 649 B4 describes a particle filter in the exhaust pipe upstream of an exhaust gas recirculation pipe for supplying a pressure wave charger, which to the knowledge of the Applicants is used for diesel engines.
US 2014/0165560 A1 describes, according to FIG. 1, an exhaust gas recirculation pipe of a diesel engine, into which a particle filter and an AMOX catalytic converter is integrated. According to Paragraph [0025], this exemplary embodiment is also intended to be used for a gasoline engine. Due to there being no need for ammonia as a reduction agent for the reduction of NOx with a constantly stoichiometric or rich-running gasoline engine, the use of an AMOX catalytic converter in the exhaust gas recirculation pipe comes into consideration for the oxidation of surplus ammonia, concomitantly the embodiment according to FIG. 1, but not for a gasoline engine.
U.S. Pat. No. 4,356,806 A describes an exhaust gas recirculation pipe for a gasoline engine with an air cooler and two downstream filters for coarse dirt.
DE 10 2010 046 900 A1 describes two variants of an exhaust gas recirculation pipe for a gasoline engine, wherein, in the main exhaust pipe upstream of the turbine, a catalytic converter and a downstream particle filter are provided. An exhaust gas recirculation pipe_I branches off upstream of the turbine and opens downstream of the compressor. Only one cooler is placed inside this exhaust gas recirculation pipe_I. An exhaust gas recirculation pipe_II branches off downstream of the particle filters and opens upstream of the compressor. Likewise, only one cooler is placed inside this exhaust gas recirculation pipe_II.
GB 2 484 495 A describes an exhaust gas recirculation pipe for a gasoline engine, contained in which are a catalytic converter, downstream a cooler, and further downstream an oxidation catalytic converter. The oxidation catalytic converter serves to carry out the oxidation of additional hydrocarbons introduced upstream for the purpose of combustion of particles.